/*
 * Copyright (c) 2022-2025 KCloud-Platform-IoT Author or Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.laokou.common.core.util;

import org.laokou.common.i18n.common.exception.SystemException;

import java.security.SecureRandom;

public final class RandomStringUtils {

	private static final SecureRandom RANDOM = new SecureRandom();

	private RandomStringUtils() {
	}

	public static String randomNumeric() {
		return randomNumeric(6);
	}

	public static String randomNumeric(int length) {
		if (length < 1) {
			throw new SystemException("S_String_InvalidLength", "随机字符串长度不能小于1");
		}
		StringBuilder stringBuilder = new StringBuilder(length);
		for (int i = 0; i < length; i++) {
			stringBuilder.append(RANDOM.nextInt(10));
		}
		return stringBuilder.toString();
	}

}
